1. Field of the Invention
This invention relates to light measuring devices and more particularly to an integrating photometer for measuring total ultraviolet exposure over a particular time interval.
2. Description of the Prior Art
A number of photometers are available in the prior art for measuring ultraviolet and other forms of electromagnetic or light energy. Some photometers are of the integrating variety to produce an output indicative of the total amount of energy received over a particular time interval. The available integrating photometers in the prior art are relatively bulky and their use often requires manipulation of controls to achieve a reading.
In connection with the manufacture of printed circuit boards, the exposure of a board and a printed circuit master to ultraviolet light sources to expose the photoetch material on the board creates a need for a measurement of the total amount of energy received by a particular photoetch coated board during the exposure sequence. Prior art ultraviolet photometers do not readily lend themselves to providing this sort of a measurement.